32 Prof. B. Moore. The Production of Growths or 



precipitation, but prolonged autoelaving throws it out of solution. The 

 amount of coaguluni when the sulphur passes out of solution demonstrates 

 that there is ultramicroscopic sulphur in colloidal solution in the fresh 

 preparation, in addition to the particles mentioned above. A determination 

 made by evaporating a known volume to dryness and weighing the sulphur 

 gave - 48 per cent, in the solution as prepared above. 



This solution was diluted tenfold before use, as was also the colloidal ferric 

 hydrate solution used for equilibration with it, so that the concentrations of 

 the two solutions as actually mixed were approximately : colloidal sulphur «, 

 0'048 per cent. ; colloidal ferric hydrate, Oi:-36 per cent. 



In order to exclude entirely growths of " organic carbon " organisms, that is 

 "living" organisms, both solutions, while still separate, were put into a steam 

 autoclave at 110° C. for 10 minutes; this caused partial precipitation. The 

 two solutions were then allowed to cool and when cold were mixed as in 

 the following scheme : — 





Test-tube. 



Number 



1. 



2. 



3. 



4. 



5. 



6. 



7 , 8. 



9. 





c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 1 cjp 





Ferric hydrate solution 



9 



8 



7 



6 



5 



4 



3 1 2 



T 



Sulphur a solution 



1 



2 



3 



4 



5 



6 



7 8 



9 



There was no complete precipitation in auy of the tubes, but a varying 

 amount of increase in the opalescence. 



Microscopic examination as rapidly as possible within a few minutes ,of 

 making the admixtures showed growths iu all, but most rapidly and 

 abundantly in test-tubes Nos. 2 and 3. Microphotographs of the growths 

 obtained when 8 c.c. of the colloidal ferric hydrate and 2 c.c. of the 

 sulphur solution were mixed are shown in fig. 2. The growths here again, 

 when sufficiently coarse, give the appearance by a yellowish colour of an iron 

 salt. 



The finest threads are only visible in dim illumination. The growths, 

 again, in this case do not yield good microphotographs. All sizes of fibre 

 are seen here from the finest fibrils up to quite coarse fibres, like structures 

 from plants. 



Spontaneous Growths in Colloidal Silicic Acid only. — It is well known from 

 the classical experiments of Graham that sufficiently dialysed silicic acid 

 solution is spontaneously metastable, and, after perhaps days, months, or 

 years of keeping, passes out into a solid jelly. It is rather remarkable that 



